I've been thinking about this as well.
I know there are separate Y-pies available, but does anyone sell
just the X or H pipe?
I agree that this plus TP or HFC would be an excellent solution for someone looking to pick up decent gains on a budget.
EDIT: Interesting commentary here regarding the differences in output, and where in the rev ange, for different set-ups.
http://www.350z-tech.com/forums/153-...ml#post1084629
In short, the recommendation is Y for low to mid range grunt and H or X for top end.
That makes me think the Y pipe might be preferable.
Does that corroborate with what folks have found for the VQ37?